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PANTOGRAPH.

Patented Jan. 6, 1885.

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wm simmk Magmmwxmm- UNITEDy STATES PATENT OEEICE.

MARC DIAMOND, OF NEW YORK, l\. Y.

PANTOGRAPH.

SPECIFICATION forming part of Letters Patent No. 310,186, datedj'anuary 6, 1885.

l .Application filed March 24,1884. (No model.)

Be it known that I, MARC DIaMoND, ofthe city, county, and State of New York, haveinvented new and useful Improvements in Fair tographs; and I do hereby declare that the following is a full and exact description thereof', reference bei ng had to the accompanying drawings, and to the letters of reference marked thereon, making apart of this specification.

The object ot' myinvention is to so brace and strengthen the pivotal joints of a pantograph and steady and support its outer free end,ear rying the pencil, as to render the instrument more exact and precise in execution and more durable.

It consists in the combination of awide base or rest with the end of the outer swinging arm which carries the pencil; in the construction ot' a tubular holder and spring for adjusting the pencil, and in the special formation, as hereinafter described, of the supporting or pivotal bearing by which the lixed end is attached to and allowed to swing above the drawing` board or table, and of the pivotal joint carrying the tracing-point.

In-the accompanying drawings, Figure l is a plan view of a pantograph with myimproved attachments; Fig. 2, a sectional view on line m of Fie'. l, showing the pivotal attachment whereby the device is secured to the table; Fig. 3, a vertical section on line y yof Fig. l., illustrating the pivotal joint carrying the tracingpoint; and Fig. 4, a vertical section on line e of Fig. 1, illustrating the end support and the springactuated mechanism i'or adjusting the pencil.

A is the first or inner arm, and A the outer working-arm, of the pantograph,and A2 and A3 its intersecting controlling-arms. The first arm, A, of the pantograph is attached to a bearing and brace block a Fie'. 2, ada )ted to receive and swing freely upon a long vertical pivot-pin, B, projecting from a circular disk, I), adapted to rest upon the table or board upon which the instrument is to be used and to which it is made fast by means ofa wood-screw,

` b', project-ing centrally from its under side.

Arms or offsets b2 b2 are 'formed upon the rimv `the pencil carried thereby.

or height of the braceblock ais such as to provide a long extended bearing therefor upon the pivotpin B, which enables it to support the swinging arm A in its free position abovethe board without the need of any additional supporting devices in the lengt-h thereof, as is found in other pantographs. The pivot C, Figs. l and3, of the jointed controlling-arms A2 A3,is formed to project from the enlarged end of a tapering pin, c, which serves as the tracing-point for the instrument. The wide end of the pin c forms a shoulder about the base of the pivot G, and is extended by means of an encircling flange, c', adapted to bear against and support the under side of the lower controlling-arm,A3. The pivot C is threaded at its outer end to screw into a plate or nut, c2, made fast upon the top of the end of the upper arm, A2. A shoulder, d, formed upon the body of the pivot C,limits the depth to whichit may bcscrewed into the nut or plate c2, so as to prevent any binding of the pivotal joint between the arms.

To the under side of the free end of the outer arm, A', carrying the pencil, is fitted and firmly secured a supportingblock, D, having a wide base extending laterally at right angles to the length of the arm, adapted to so support the arm in its movements over the table or paper, and prevent, by its broad even bearing, any rocking or twisting of the arm or tipping of lThe pencil is mounted at the end ol' this arm A within a slotted tube, E, whose lower end is adapted to screw into and through the arm and its snpporting-block, as shown in Fig. 4, so as to afford a longextended bearing l'or the pencil,

which is free to drop through it and rest upon by a spiral spring, F, coiled loosely thereon, r

and the lower end of this spring is made fast to an annular disk or thumb-plate, G, encircling the tube E upon the top of the arm, and which is held in place by an annular plate or disk, H, fixed to the tube. A laterally-pro jecting pin, I, is lixed to the pencil near its upper end to pass into the slot andproject out through the same between the coils of the spring, so that as the spring is revolvedin the one direction or the other by means of the thumbplate G its spiral coil engaging the pin IOO will cause the pencil to move up or down, so that its point may be thereby adjusted to bear upon the paper with more or less pressure.

My improved pivotal attachment gives to the pantograph, by reason of its extended bearing upon the pivot-pin B, a firm,accurate support, whereby it may swing over the paper at the proper elevation without additional su pport, while the extended base furnished by the block D at the free end of the device, and the firm support given to the pencil by means of the tube E, serve to maintain it invariably in its proper vertical position, thus rendering the whole device more accurate than the pautograph heretofore in use.

The tracing-point c may be made of hard rubber, and,as it serves asa pivot for the controlling-arms, the latter are always properly centered thereby. Moreover, by making the upper end of the point fast to the upper arm so that it may serve as a pivot for thelower arm, the difficulty which results from theloosening of the joint in the pantographs heretofore constructed by reason of the working loose of the nut upon the upper end of the point when the upper arm is free to move underit is wholly ob- Viated, and thejoint remains constantly firm and reliable.

I claim as my inventionl. The combination, with the outer end of the pencil-arm of a pantograph, of a supportingblock, D, secured thereto, the longer horizontal axis of which is at right angles to the length ofthe arm, and adapted to slide upon the surface over which the arm is extended, and l[hereby prevent a rocking of the arm, substantially in the manner and for the purpose herein set forth.

2. The combination, with a longitudinallyslotted tube, E, secured to the pencilarm of a pantograph to project upwardly therefrom and receive and guideitspencil, of a spiralspring, F, encircling the tube, secured at its lower end to a ring or collar, G, rotating upon the tube, and whose coils are adapted to engage a pin projecting` from the pencil through the slot in the tube, substantially in the manner and for the purpose herein set forth.

3. The combination, with the jointat the intersection with each other of the controllingarms A2 A3 of a pantograph, and with a de tachable tracing pin or' point, C, adapted io serve as the pivot for said joint, of a nut or threaded socket, C, rigidly secured to the upper superimposed arm, so as to engage and hold the pin upon which the lower arm only is left free to turn, substantially in the man ner and for the purpose herein set forth.

In testimony whereof I have signed 1n y name to this specification in the presence of two subscribing witnesses.

MARC DIAMOND.

"Witnesses:

A. B. MOORE, G. M. VooDoooK. 

